Method and apparatus for dual-band mesh operations

ABSTRACT

Methods and apparatus may perform dual-band or multi-band mesh operations. A dual-band mesh station (MSTA) capable of operating in an O-band and a D-band may seek to join a mesh network, and may receive O-band beacons from at least one MSTA in the mesh network, where the O-band beacons may include D-band mesh information. The joining MSTA may transmit D-band beacons in a time-period specified by the O-band beacon, and on a condition that a beacon response message is received, may further transmit D-band association information via O-band management frames to join mesh network on the D-band. The joining MSTA may perform contention-free scheduled access in the D-band while sharing D-band transmission information in the O-band to enable concurrent communication in the D-band by neighboring multi-band MSTAs.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage, under 35 U.S.C. § 371, ofInternational Application No. PCT/US2015/020465 filed Mar. 13, 2015,which claims the benefit of U.S. Provisional Application No. 61/953,459,filed Mar. 14, 2014, the contents of which are hereby incorporated byreference herein.

BACKGROUND

Wireless devices have been developed that may operate, for example, inthe O-band (<6 GigaHertz (GHz)) and/or the D-band (>28 GHz). Devicesthat operate in both bands may be referred to as dual-band devices, andthe use of dual-band devices is increasing. Wireless stations maycommunicate with each other in peer-to-peer fashion. Such peer-to-peeroperation may result in mesh operations. A mesh network device may bereferred to as a mesh station.

SUMMARY

Methods and apparatus may perform dual-band mesh operations. Dual-banddevice discovery and beamforming training may include the use of bothD-band and O-band transmission ranges. A mesh station (MSTA) may join anexisting mesh and receive information concerning the mesh profile andmesh transmission schedules. The new mesh station may use thetransmission schedule information to conduct a Sector Level Sweep (SLS)without interfering with the beacons of the MSTAs currently operating inthe mesh and without spatial overlap. One MSTA may perform a sectorsweep in a slot different from that used by another MSTA.

Two MSTAs in the mesh network may transmit to each simultaneously. MSTAsmay prioritize transmission schedules based on quality of service (QoS),and/or the capabilities of the MSTAs. MSTAs may route data based ontransmitting in multiple bands and interference minimization. The MSTAsmay use both 802.11ad and 802.11s procedures, conduct mesh peering anduse buffer status information.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingsfurther comprising:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A;

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A;

FIG. 2 is a diagram of an example SLS scheduling procedure 200 for amesh station (MSTA) joining an existing mesh network;

FIG. 3 is a signaling diagram of an example periodic beamformingprocedure where periodic beamforming (BF) training periods are scheduledwith multiple Association-Beam Forming Training (A-BFT) slots;

FIG. 4 is a signaling diagram of an example periodic beamformingprocedure where periodic BF training periods are scheduled with a singleA-BFT slot;

FIG. 5 is a diagram of an example 802.11s beacon frame body;

FIG. 6 is a diagram of an example Mesh Coordinated Channel Access (MCCA)Setup Request Frame;

FIG. 7 is a diagram of an example of an MCCA Advertisement Element;

FIG. 8 is a diagram of example dual band mesh network showing exampletransmission ranges for 60 GHz and 5 GHz;

FIG. 9 is a signaling diagram of an example neighbor STA assisted802.11ad link establishment procedure using GPS information;

FIG. 10 is a signaling diagram of an example interference measurementprocedure from the perspective of a measuring MSTA;

FIG. 11 is a system and signaling diagram of an example multi-bandrouting and scheduling procedure; and

FIG. 12 is a diagram of an example Mesh Link Metric Report element.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the other networks 112. By way of example, the base stations 114a, 114 b may be a base transceiver station (BTS), a STA-B, an eSTA B, aHome STA B, a Home eSTA B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaySTAs, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple-output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as Institute for Electricaland Electronics Engineers (IEEE) 802.16 (i.e., WorldwideInteroperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×,CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95(IS-95), Interim Standard 856 (IS-856), Global System for Mobilecommunications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSMEDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home STA B,Home eSTA B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 106.

The RAN 104 may include eSTA-Bs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eSTA-Bs whileremaining consistent with an embodiment. The eSTA-Bs 140 a, 140 b, 140 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eSTA-Bs 140 a, 140 b, 140 c may implement MIMO technology. Thus, theeSTA-B 140 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eSTA-Bs 140 a, 140 b, 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1C, theeSTA-Bs 140 a, 140 b, 140 c may communicate with one another over an X2interface.

The core network 106 shown in FIG. 1C may include a mobility managemententity gateway (MME) 142, a serving gateway 144, and a packet datanetwork (PDN) gateway 146. While each of the foregoing elements aredepicted as part of the core network 106, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MME 142 may be connected to each of the eSTA-Bs 140 a, 140 b, 140 cin the RAN 104 via an Si interface and may serve as a control STA. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eSTA Bs 140 a,140 b, 140 c in the RAN 104 via the Si interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eSTA B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices. An access router (AR) 150 of a wireless local area network(WLAN) 155 may be in communication with the Internet 110. The AR 150 mayfacilitate communications between APs 160 a, 160 b, and 160 c. The APs160 a, 160 b, and 160 c may be in communication with stations (STAs) 170a, 170 b, and 170 c.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

A WLAN in an Infrastructure Basic Service Set (BSS) mode may have an APfor the BSS and one or more MSTAs associated with the AP. The APtypically may have access, or interface, to a Distribution System (DS),which may connect the BSS to other wired/wireless network(s) that maycarry traffic outside of the DS. Traffic to MSTAs that originates fromoutside the BSS may arrive through the AP and may be delivered to theSTAs. Traffic originating from MSTAs to destinations outside the BSS maybe sent to the AP to be delivered to the respective destinations.Traffic between MSTAs within the BSS may also be sent through the APwhere the source STA may send traffic to the AP and the AP may deliverthe traffic to the destination STA. Such traffic between MSTAs within aBSS may be considered peer-to-peer traffic. Such peer-to-peer trafficmay also be sent directly between the source and destination MSTAs witha direct link setup (DLS). Example protocols for DLS include, but arenot limited to, 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN usingan Independent BSS (IBSS) mode may have no AP and MSTAs may communicatedirectly with each other. This mode of communication may be referred toas an “ad-hoc” mode of communication.

IEEE 802.11 standards include specifications for implementing WLAN withdifferent architectures and operating in a variety of frequency bands.For example, IEEE 802.11s is a standard for mesh networking with theintention of defining how wireless devices can interconnect to create aWLAN mesh network that may be used for static topologies and ad-hocnetworks. An 802.11s mesh network device may be labeled as a MeshStation (MSTA). MSTAs may form mesh links with one another, over whichmesh paths may be established using a routing protocol. 802.11s extendsthe IEEE 802.11 MAC standard by defining an architecture and protocolthat support both broadcast/multicast and unicast delivery usingradio-aware metrics over self-configuring multi-hop topologies.

According to 802.11ad, for example, Very High Throughput transmissionsmay use the 60 GHz band. Wide bandwidth spectrum at 60 GHz is available,thus enabling very high throughput operation. 802.11ad may support up to2 GHz operating bandwidths and the data rate may reach up to 6Giga-bits-per-second (Gbps). The propagation loss at 60 GHz may be moresignificant than at the 2.4 GHz or 5 GHz bands, thus beamforming hasbeen adopted in 802.11ad as a means to extend the coverage range.

Another example feature of the 802.11ad is scheduled channel access modein addition to contention-based access. This may allow an AP and a STAto gain predictable access to the channel. Further, in addition to theIBSS, 802.11ad may use a Personal Basic Service Set (PBSS) as an ad-hocnetwork. Similar to the IBSS, the PBSS may be a type of IEEE 802.11 LANin which MSTAs may communicate directly with each other. In contrast tothe IBSS, in a PBSS a STA may assume the role of the PBSS control point(PCP).

Tri-band enabled chipsets may enable combinations of 802.11transmissions including, but not limited to, 802.11n/802.11ac/802.11adtransmissions. Devices incorporating these multi-band chipsets may formmulti-band mesh networks and derive the resulting benefits. Examples ofpossible benefits of multi-band mesh networks, which may include atleast one O-band channel (<6 GHz) and one D-band channel (>28 GHz),include, but are not limited to, any of the following. For example,dual- (or multi-) band mesh networks may have omnidirectionaltransmission capability in O-band, which may provide improved coverageand reliability, and may leverage the large available bandwidths andspatial multiplexing available at higher frequencies. In anotherexample, due to directional transmission in D-band, mutual interferencebetween neighboring MSTAs may be significantly reduced, and may allowmultiple simultaneous directional transmissions between neighboring STApairs. As a result, data transmissions in a directional mesh network maynot be affected by the channel access limitations seen in O-band meshes,thereby improving the overall network capacity. According to anotherexample, due to greater range in O-band, low data rate data includingfor example control packets, may be sent in the O-bands, althoughcertain time critical data may not. Additionally, in case of occasionallink failures in D-band due to obstructions or other reasons, O-bandchannels may be used for regular data transmission.

Approaches to improve operations in dual-band mesh networks aredescribed herein. For example, during 802.11ad beamforming stage SectorLevel Sweep (SLS), directional beacons may be transmitted in multipledirections by a STA, which may potentially interfere with ongoing802.11ad based transmission(s) in the system. This may requirecoordination among neighbor MSTAs including 1-hop, 2-hop (or more hop)neighbors, and/or an MSTA that wants to join the network. 802.11s beaconcollision avoidance mechanisms may rely on, for example, completelysilencing the beacon transmission of the MSTA during the known beacontransmission time of the neighbors. This approach may be toorestrictive, may add excessive delay, and may not effectively use thespatial separation in the scenario of multiple directional beacontransmission of SLS phase of 802.11ad. To address these issues,according to an embodiment described herein, a beacon beamformingscheduling mechanism may be based on the transmission scheduling ofneighbor MSTAs.

In another example, 802.11s beacon frame information elements (IEs) aswell as management frames such as Mesh Coordinated Channel AccessOpportunity (MCCAOP) set-up request, MCCAOP set-up reply, and MeshCoordinated Channel Access (MCCA) advertisements, may not be capable of802.11ad related information such as SLS scheduling, 802.11adTransmission Opportunity (TXOP) request, and/or 802.11ad basedtransmit-receive (TX-RX) reports and/or interference reports. Hence,such IEs or frames may not be able to be used to schedule 802.11adframes for beamforming training and/or data scheduling. Thus, accordingto an embodiment described herein, 802.11s beacon IEs and/or managementframes may include directional scheduling information.

According to another example, the transmission range in sectorized 60GHz transmission may be longer than sub 5 GHz at the same STA due tointerference and/or heavy traffic load in 5 GHz. In this case, a STAthat is not in the range of 802.11s but in the range of 802.11ad may notbe able to employ mesh peering (i.e. mesh peer communications) with therequestor STA. Moreover, O-band management frames initiated by therequestor STA may not be used for 802.11ad beamforming or beacontransmission scheduling. In such cases, according to an embodimentdescribed herein, the management frames transmitted by 802.11s may beconveyed via 802.11ad frames instead or in addition to the 802.11sframes. An example procedure may be applied where the MSTAs may carry onmesh peering via 802.1 lad frames, as described herein.

According to another example, a 802.11s data scheduling mechanism, suchas MCCA, may allow only a particular MSTA pair to transmit among the2-hop neighbors in order to minimize the effect of interference withinthe mesh network. However, for data transmission using directional802.11ad frames, allowing only one particular pair within the cluster tocommunicate at a time may result in spectral inefficiency. According toan embodiment described herein, an 802.11s procedure may incorporate thespatial transmission information in the scheduling.

According to another example, an 802.11s data scheduling mechanism, suchas MCCA, may not make use of packet Quality of Service (QoS)requirements and/or ordering of user access depending on the trafficrequirements. The requestor STA may transmit an MCCA set-up frame basedon the TX-RX report of the destination STA. The buffer status report(BSR) may not be exchanged between the requestor and destination STA.For a highly loaded system, this approach may not guarantee QoS-basedtraffic flow. According to an embodiment described herein, a mechanismmay guarantee QoS requirements of the traffic flows, such that actionsmay be incorporated into 802.11s system procedures.

According to another example, 802.11s routing procedure may be based onsingle channel metric determination and selection of the paths based onthe aggregated metrics at the STAs. On the other hand, for multi-channeloperation such as in 802.11s and 802.11ad capable STAs, each STA mayhave multiple channels (e.g., O-band and/or D-band) to select andforward a packet. 802.11s airtime link metrics may not map to multiplechannels. Also, selection of an O-band channel may inherently hinderother (possibly interfering) neighbor MSTAs to transmit. According to anembodiment described herein, a modification may be included in theairtime link metric of 802.11s to address these issues.

According to another example, 802.11s management frames may betransmitted in a contention-based fashion. In highly loaded andpotentially interfering networks, the reception of these packets may notbe guaranteed and that may impact the scheduling of 802.11ad datapackets. To guarantee transmission of 802.11ad scheduling packets using802.11s management frames, contention-free mechanism or prioritizationof management frames may be adopted, in accordance with an embodimentdescribed herein.

Although examples of dual-band mesh operations are described herein withrespect to O-band and D-band, the techniques may apply to other bandsthat may be used in a multi-band mesh network and may use networkprotocols 802.11s, 802.11ad or any other wireless networking protocol.While two frequency bands are described, it is possible to extend it toother frequency bands for multi-band mesh network operations.

According to procedures described herein, methods may be used for802.11s based neighbor discovery and mesh peering and may include802.11ad capabilities of the STAs. In the following examples, it may beassumed that MSTAs have dual-band capability, with for example 802.11sand 802.11ad functionalities in the O-band (omnidirectional transmissioncapabilities) and the D-band (directional transmission capabilities),respectively.

802.11s management frames may be used to inform the neighbor MSTAsregarding the ongoing neighbor 802.11ad transmissions. The newly joiningMSTAs may select their 802.11ad SLS patterns based on this informationto avoid interference at the MSTAs.

D-band beacon transmission may be triggered by new STA discovery inO-band. This may reduce the time overhead associated with beacon andsector sweep frame transmission. In IEEE 802.11ad, beacon and sectorsweep (SSW) frames may be transmitted during the Beacon TransmissionInterval (BTI) and Association-Beam Forming Training (A-BFT) periods,respectively. To quantify the time savings in an example scenario, itmay be assumed that there are 64 slots reserved for beacon transmissionsand SSW frames in BTI and A-BFT, respectively. Beacon frames may carryextended schedules for four transmissions and there may be four A-BFTslots for contention resolution during A-BFT.

In the example scenario above, the BTI and A-BFT periods together mayuse approximately 36 milliseconds (ms). In a beacon interval lasting 100ms, this may constitute approximately 36% overhead, and thus may reducetransmission efficiency proportionately. A method may be used to obviatethe need for beacon transmissions and SSW slots in D-band, withassociated gains in MAC efficiency.

FIG. 2 is a diagram of an example SLS scheduling procedure 200 for anMSTA 210 newly joining an existing mesh network. In the example of FIG.2, the existing mesh network includes nodes or MSTAs 202, 204, 206, and208, and two transmission opportunities (TXOPs) are shown, TXOP 212 andTXOP 214. During TXOP 212, MSTA 210 may select the beacon directionsfrom the set of beacons shaded grey including 220 ₁, 220 ₂, 220 ₃, 220₆, 220 ₇, and 220 ₈. During TXOP 214, the candidate set of beacons forMSTA 210 (shaded grey) includes beacons 220 ₁, 220 ₄, 220 ₅, 220 ₆, 220₇, and 220 ₈. MSTA 210 may avoid sector sweep using beams that wouldinterfere with existing mesh transmissions, such as beams 220 ₄ and 220₅ in TXOP 212, that may interfere with reception at MSTA 206, and beams220 ₃ and 220 ₄ in TXOP 214 that may interfere with reception at MSTA208.

According to an example SLS scheduling procedure, with reference to FIG.2, MSTA 210 may become part of the mesh network in the 802.11s layer(O-band). Then, MSTA 210 may establish 802.11ad (D-band) links with theneighbors discovered using 802.11s. Hence, MSTA 210 may initially carryout peering procedures in O-band, as described further below.

The peering procedure in O-band may include authentication procedures atD-band as well, and may be needed for information exchange between theMSTAs of the mesh network communicating in D-band. Then, the new MSTA210 may continue with beamforming/beam refinement procedures in 60 GHzwith the neighbor STAs, such as MSTAs 202, 204 and/or 206, in order toestablish high rate links in between. The beamforming procedure mayrequire SLS both at the new MSTA 210 and existing MSTAs (e.g., MSTAs202, 204 and/or 206). 802.11s signaling may be used to minimize theinterference due to SLS in 60 GHz, as described below.

MSTA 210 may join the network using a first band, in this example O-bandor 802.11s, as follows. MSTA 210, which may be a new STA in the meshnetwork, may read the 802.11s beacons transmitted by the neighbor STAs,e.g., MSTA 202, MSTA 204, MSTA 206, and/or MSTA 208. If no beacon isreceived within a predetermined period, MSTA 210 may broadcast probeframes and wait for the probe response.

The MSTAs 202, 204, 206 and 208 of the mesh network may include a meshprofile in the beacon and/or probe response frame. The mesh profile maybe provided via a mesh identifier (ID) and/or mesh configurationelements. A mesh profile may include 802.11s profile elements including,but not limited to: Mesh ID, path selection protocol identifier, pathselection metric identifier, congestion control mode identifier, and/or802.11ad (D-band) capability element. The 802.11ad capability elementsmay include D-band related information such as the antenna capabilityand/or maximum TX-RX range.

In an example, if the mesh profile of candidate MSTA 202 matches withthe profile of the network's profile both in 802.11s and 802.11ad, thenMSTA 202 may be considered as a candidate peer MSTA. MSTA 210 maydetermine an active mesh profile and may be added to the mesh network bycarrying out the authentication procedures with MSTA 202. MSTA 210 mayperform Target Beacon Transmission Time (TBTT) selection in 802.11sbased on the beacon timing information obtained from the neighbors viaadvertisement frames. Based on the available TXOP, MSTA 210 may scheduleparticular TXOPs as beacon transmission and inform neighbors,accordingly, via management frames, such as advertisement frames forexample.

After being added to the network via an existing MSTA such as MSTA 202,MSTA 210 may proceed with O-band mesh peering with other candidate MSTAs(e.g., MSTAs 204, 206, 208) that are already members of the meshnetwork. This action may include the authentication procedure in O-bandand/or D-band so that the MSTAs 204, 206, 208 may proceed with datatransmission/reception procedures in these bands.

According to an embodiment, link establishment may be 802.11ad based.For example, the joining MSTA (e.g., MSTA 210 in FIG. 2) may transmitD-band beamforming request to an MSTA in the mesh network (e.g., MSTA202 in FIG. 2), or vice versa. The request may be included in the802.11s beacon or another management frame. In another example, 802.11sdata slots may be used to inform the 802.11ad beamforming request. Thebeamforming request may include the starting time of the procedure, forexample, the SLS initiation time by the requestor MSTA (e.g., eitherMSTA 210 or MSTA 202).

Also, the requestor or initiator MSTA (e.g., either MSTA 210 or MSTA 202in FIG. 2) may go through an SLS procedure. The SLS may be carried by802.11ad sector sweep (ScS) frames. Before starting this procedure,however, the initiator MSTA may receive 60 GHz (802.11ad) transmissionschedule information of the first tier (i.e. one-hop) neighbors and/orsecond tier (i.e. two-hop) neighbors. The 802.11ad schedulinginformation for the initiator MSTA's first tier neighbor MSTAs and/orsecond tier neighbor MSTAs (neighbors that connect to the initiator MSTAthrough the first tier neighbors) may be conveyed via 802.11s beacons ormanagement frames by each of the discovered dual-band capable neighbors.The 802.11s management frame structure may include the TX-RX period,broadcast period and interference period in 802.11ad by the neighborSTAs. This information may be incorporated into the MCCAOP Overviewelement and MCCAOP Advertisement element.

Further, the advertisement elements regarding 802.11ad transmission mayinclude either the direction of transmission or a combination ofreceiver STA ID and interference table as well which might be utilizedby the joining MSTA (e.g., MSTA 210 in FIG. 2) in determining its SLSsweep direction set.

For example, with reference to FIG. 2, the joining MSTA 210 may wait toreceive the MCCAOP Overview element and MCCAOP Advertisement elementfrom all neighbors the joining MSTA 210 completed a mesh peeringprocedure with.

Based on the received advertisement elements including receiver IDs andinterference tables, the initiator MSTA (e.g., either MSTA 210 or MSTA202 in FIG. 2) may determine a SLS schedule that does not spatiallyoverlap with any of the ongoing directional transmissions. This schedulemay be communicated to the immediate neighbors via 802.11s messages.This schedule may be further transmitted by the one-hop neighbors totheir own one-hop neighbors (i.e. two-hop neighbors of the initiatorMSTA), so that they do not schedule new TXOPs with their neighborsduring those periods.

According to another embodiment, the MSTAs may have GPS information. Forexample, with reference to FIG. 2, MSTA 210 may receive the TX-RX reportfrom MSTA 202 and therefore has the information of scheduledtransmission in the network. Based on the location information andtransmission scheduling of the neighbor STAs, MSTA 210 may selectbeam-sweeping pattern such that the SLS does not potentially interferewith the ongoing and upcoming neighbor (e.g., first and/or second tierneighbors) 802.11ad transmissions.

In one example, with reference to FIG. 2, since MSTA 202 is already amember of the network, it may have the information of which beamdirections/beam numbers (from its perspective) might create interferenceto the scheduled neighbor 802.11ad transmissions. MSTA 202 may informMSTA 210 regarding the interference directions along with thecorresponding MCCAOPs. After receiving this information, MSTA 210 maydetermine its directional beacon transmission pattern according to therelative location information with respect to MSTA 202.

According to another embodiment, the MSTAs may not have GPS information,but may have orientation (e.g., via a compass). Further, the STA may usethe direction information of the neighbor STAs' transmissions and avoidscheduling the SLS patterns which include those directions.

After determining SLS sweep directions as well as the scheduling,initiator MSTA may inform neighbor MSTAs regarding its SLS schedule inD-band. A selected SLS schedule may be transmitted via 802.11smanagement frames to one-hop neighbor MSTAs and/or to the two-hopneighbor MSTAs (via 1-hop neighbors). The receiving neighbor MSTAs thathave not established directional beam with respect to the initiator MSTAmay use these schedules to receive SLS procedures.

The following procedures describe example methods for a dual-band (e.g.,60 G Hz or D-band, and O-band or 2.4 GHz/5 GHz/Sub-1 GHz) mesh capableSTA joining a dual-band mesh network that provides for regularbeamforming periods in the 60 GHz band. As described above, initialtopology for a newly joining STA may be determined by connectivity inthe O-band, which may reduce based on 60 G Hz connectivity. According toan embodiment, network discovery may occur in the O-band, while topologyfor the new STA may be determined by connectivity in the 60 GHz band(e.g., D-band).

Existing MSTAs (i.e., already in the mesh network) may allocate time inthe 60 GHz band for beamforming training with new MSTAs that are tryingto join the mesh network. Other 60 GHz transmissions may not bescheduled during this periodic allocation, which is common to all meshSTAs. The new (joining) STA may start operation in the O-band, and maydiscover the 60 GHz band beamforming period information either bypassive listening or by O-band message exchange. It may then perform anSLS phase of beamforming training with each neighboring dual-band STA insuccession. O-band association may be performed with a particular subsetof the dual-band MSTAs that are also reachable in O-band.

Some advantages to this approach may include any of the following. TheO-band communication range may be larger than 60 GHz range, for example,in the case that the O-band uses sub-1 GHz band. In this case, the newSTA may have fewer neighbors visible in the 60 GHz than in O-band, andmay save time by avoiding trying to perform beamforming training withunreachable MSTAs in 60 GHz. This approach applies to the SLS phase of802.11ad BF training procedure.

The following procedure describes one example of how a new STA (MSTA)may perform initial beamforming training when beamforming (BF) trainingperiods are scheduled periodically. FIG. 3 is a signaling diagram of anexample periodic beamforming procedure 300 where periodic BF trainingperiods are scheduled with multiple A-BFT slots. In the example of FIG.3, new MSTA 302 is trying to join an existing mesh network includingMSTA 304 and MSTA 306 (the mesh network may include other MSTAs notshown).

The new MSTA 302 may start operation in O-band and may scan for beacontransmissions from neighboring dual-band mesh STAs, for example theO-band beacon transmission 308 from MSTA 304. The new MSTA 302 maytransmit a Probe Request (not shown) if it does not hear a beacontransmission after a predetermined time duration.

The O-band beacon 308 (or Probe Response frame in response to a ProbeRequest) may contain parameters used in 60 GHz band operation including,but not limited to, channel number and/or supported data rates. TheO-band beacon 308 may also include, but is not limited to, beamforming(BF) training period information. For example, the beacon 308 (or ProbeResponse frame) may contain the start time and duration of the next 60GHz BF training period 311. The parameters used for 60 GHz operation maybe included in the O-band beacons 308 (or Probe Response messages), suchthat the new MSTA 302 may not associate with an MSTA in the mesh networkto obtain these parameters.

The O-band beacon 308 may also include, but is not limited to, otherD-band related information such as: D-band capable, D-band channelnumber, D-band mesh ID, D-band capability, D-band beacon interval,D-band beacon interval control, D-band mesh configuration and/or D-bandBF training period information. MSTAs 304 and 306 may be mesh peeringand may exchange 60 GHz (D-band) transmissions 303 and 305, includingdata transmissions, directly with each other.

At the indicated start time of the periodic 60 GHz beamforming (BF)training period 311, the new MSTA 302 may start transmitting beacon orsector sweep (SSW) frames 314 in a slotted manner in multipledirections. This may comprise the Beacon Transmission Interval (BTI)316. During this time referred to as the initiator sector sweep 312,MSTAs 304 and 306 may receive signals with the widest antenna patternrealizable (e.g., quasi-omni pattern). When an MSTA hears a beacontransmission it may perform a responder sector sweep 313 by transmittingSSW frames. For example, MSTA 306 may perform sector sweep transmissions322 in a slotted manner to new MSTA 302 during responder sector sweep313.

Either transmit or receive responder sector sweep 313 may be possibleduring the Association Beamforming Training (A-BFT) period 318, and themode may be determined by the appropriate fields in the received beaconor SSW frame 314 during the preceding BTI 316.

When multiple MSTAs receive the beacon or SSW transmissions 314 (alsoreferred to as sectorized frame transmissions 314) by the new MSTA 302,two or more or all of them may respond during A-BFT period 318, whichmay result in collision. To avoid response collision, A-BFT 318 may havemultiple (e.g K) response slots 310 ₁ . . . 310 _(K), and each slot 310₁ . . . 310 _(K) may have multiple sub-slots, for multiple sectortransmissions. MSTAs may choose a particular slot randomly or by someother manner to transmit SSW frames. For example, the MSTA 306 mayrandomly choose A-BFT slot 310 ₁ for the sector sweep transmissions 322.The MSTA 304 may randomly choose A-BFT slot 310 _(K) for the sectorsweep transmissions 324. The number of A-BFT slots K may be indicated inthe beacon or SSW frames 314 transmitted by new MSTA 302 during BTI 316.This may reduce the collision probability because each mesh STA mayindependently pick a random A-BFT slot 310 ₁ . . . 310 _(K) to transmitits response. After the training period 311, MSTAs 304 and 306 mayexchange 60 GHz (D-band) transmissions 330 and 332, including datatransmissions, directly with each other, or exchange 60 GHz (D-band)transmissions 334, including data transmissions with other MSTAs.

According to another embodiment, SSW frames collisions may also beavoided using O-band signaling. This approach may use a single A-BFTslot, for example. FIG. 4 is a signaling diagram of an example periodicbeamforming procedure 400 where periodic BF training periods arescheduled with a single A-BFT slot. In the example of FIG. 4, new MSTA402 is trying to join an existing mesh network including MSTA 404 andMSTA 406 (the mesh network may include other MSTAs not shown). MSTAs 404and 406 may be mesh peering and may exchange 60 GHz (D-band)transmissions 407, including data transmissions, directly with eachother.

The new MSTA 402 may start operation in O-band and may scan for beacontransmissions from neighboring dual-band mesh STAs, for example theO-band beacon transmission 408 from MSTA 404. The O-Band beacon 408 mayinclude BF training period information, among other information. As inthe case described in FIG. 3, the new MSTA 402 may transmit a ProbeRequest (not shown) if it does not hear a beacon transmission after apredetermined time duration.

During 60 GHz BF training period 418, a MSTA part of the mesh network,such as MSTA 406, may signal a successful 60 GHz beacon 409 or SSW framereception to the new MSTA 402 via an O-band response message 410, whichmay include an A-BFT request. The new MSTA 402 may reserve the followingA-BFT slot 419 for the use of the responding MSTA's 406 use and mayconfirm the reservation or A-BFT grant via an O-band response message412 to the MSTA 406. Other responding MSTAs (e.g., MSTA 404), if any,may also successfully receive a 60 GHz beacon 414 or SSW frame, andsignal the same to the new MSTA 402 via an O-band response message 416,which may include an A-BFT request.

The MSTA 404 may not receive the reservation confirmation from the newMSTA 402, due to prior reservation of A-BFT slot by MSTA 406, and maydefer transmission during the A-BFT period 432. During the followingA-BFT slot 419, MSTA 404 may transmit SSW frames 420 to the new MSTA402. The new MSTA 402 may send a Sector Sweep Feedback (SSW-Fbck) frameto MSTA 406. In a subsequent 60 GHz BF training period, comprising a BTIand A-BFT periods 430 and 432, the new MSTA may perform beacon or SSWtransmissions 434. Assuming beacon 436 is successfully received by MSTA404, MSTA 404 may respond with an O-band response message 438 and mayinclude an A-BFT request. The new MSTA 402 may reserve the followingA-BFT slot 432 for the responding MSTA's 404 use and may confirm thereservation or A-BFT grant via an O-band response message 440 to theMSTA 404.

The new MSTA 402 may complete the SLS procedure with all its neighborsby repeating the above actions in multiple BF training periods. When nomore neighbors are found, which may be indicated by no more responsesduring A-BFT period, the new MSTA 402 may perform association with theMSTA in O-band. It is possible that few of the MSTAs are dropped by thenew MSTA 402 at this stage, due to low SNR or other reasons. The newMSTA 402 may additionally perform D-band association or mesh peering.

During the SLS procedure 418 of the new MSTA 402, MSTA 406 may send aSLS response via O-band signaling 410, which may include an A-BFTrequest. The new MSTA 402 may send O-band response signal 412 to grantA-BFT with MSTA 406. The MSTA 404, at a given interval during the newMSTA 402's SLS 418 and D-band beacon transmission 414 time interval, maytransmit an O-band response signal 416, which may include an A-BFTrequest. Similarly, MSTA 406 may carry out SLS by transmitting D-bandbeacons 420 during an SLS interval 422. This interval may be selectedorthogonal to the new MSTA SLS interval 418 to avoid contention.

The new MSTA 402 may respond to MSTA 406's SLS operation by sending aresponse beacon 424 to feedback the SLS measurement related outputs. TheMSTAs may transmit data via D-band signals 426 and 428 by the beaconsscheduled in the previous SLS and A-BFT intervals. In the upcoming timeintervals, the D-band SLS transmission (A-BFT) and O-band feedbackprocedure may be carried out between the new MSTA 402 and MSTA 404, viathe BTI interval 430, A-BFT interval 432, beacon or SLS interval 434.

The new MSTA may send D-band beacon 436 where MSTA 404 send the O-bandsignal 438 to request an A-BFT grant. The new MSTA 402 may send thegrant via O-band signal 440. Accordingly, following the initiator SLSperiod 446, the MSTA 404 may proceed with SLS transmission 442 withinthe responder sector sweep interval 448. The new MSTA 402 may then sendthe SLS feedback to MSTA 404 via D band beacon 444.

According to an embodiment, a procedure for O-band-assisted D-bandbeamforming training is described herein. A D-band beamforming trainingprocedure may be used when D-band MSTAs initiate such a procedure duringperiodically scheduled BF training periods. Because some of the D-bandbeacon information is included in the O-band beacon or probe responseframes, the D-band frame size may be reduced thereby resulting in ashorter BF training period.

A newly joining MSTA may start operation in the O-band and scan forbeacon transmissions from neighboring dual-band MSTAs that are alreadypart of the mesh network. The new MSTA may transmit a probe request ifit does not hear a beacon transmission within a certain period.

The beacon or probe response frame may contain parameters used in 60 GHzband operation including, but not limited to, channel number and/orsupported data rates, a start time and/or duration of the next 60 GHz BFtraining period. 60 GHz operation parameters may be included in theO-band beacons or probe response messages, such that the new STA may notassociate with an MSTA to obtain these parameters.

The new MSTA may initiate D-band reception after receiving the firstbeacon frame from a dual-band capable MSTA, where the beacon frame mayinclude, but is not limited to, D-band related information. A firstprobe response frame may be received instead of a first beacon frame, ifno D-band BF training period start time is included in the O-bandframes. D-band related information in the O-band beacon may include, butis not limited to: D-band capable, D-band channel number, D-band meshID, D-band capability, D-band beacon interval, D-band beacon intervalcontrol, D-band mesh configuration and D-band BF training periodinformation.

The MSTA may activate its D-band receiver before the indicated start ofthe BF training period, if included in the O-band messages. At the startof the periodic BF training period, D-band MSTAs may transmit beacon orSSW frames in a slotted manner in multiple directions. This may occurduring the BTI. During this time, the dual-band capable new MSTA mayreceive with a wide antenna pattern (e.g., a quasi-omni pattern).

When the new MSTA receives a beacon transmission, the new MSTA mayperform responder sector sweep by transmitting SSW frames. Eithertransmit or receive sector sweep is possible in this phase, and the modemay be determined by the appropriate fields in the received beacon orSSW frame during the preceding BTI. This may correspond to the A-BFTperiod of 802.11ad. When the new MSTA receives sectorized beacons frommultiple MSTAs in a single BTI, it may respond to one of them in theA-BFT period. This prioritization to select one of the multiple MSTAs torespond to may be based on, but is not limited to the followingexamples: received signal strength of the received beacons and/orcapability information included in the beacons.

The new MSTA may complete the SLS procedure with all its neighbors byrepeating the above actions in multiple BF training periods. When nomore neighbors are found, the new STA may perform association or meshpeering with the MSTAs in the O-band. Some MSTAs may be dropped by thenew MSTA at this stage, due to low SNR or for other reasons. The newMSTA may additionally perform D-band association or mesh peering.

According to an embodiment, a procedure for a dual-band capable MSTAjoining a dual-band mesh via the D-band is described herein. Accordingto this procedure, the new MSTA may perform any of the following: startoperations in the D-band; discover its neighbors; perform associationand/or mesh-peering with each discovered neighbor in D-band; obtainO-band mesh parameters; and/or perform O-band association or meshpeering with the same MSTAs. The O-band communication range may belarger than the D-band or 60 GHz range, especially if O-band uses sub-1GHz frequencies, which may benefit this approach.

In this case, the new STA may have fewer neighbors in D-band, and maytherefore avoid associating or mesh peering with MSTAs in O-band thatare unreachable in D-band. Moreover, O-band mesh related information maybe provided to the new MSTA via D-band message exchange, and thereforeO-band scanning may be skipped. In another example, the STA mayassociate with other MSTAs that are reachable in O-band, but not inD-band.

The example procedures are described herein with respect to twofrequency bands, however, it is possible to extend it to other frequencybands and more than two frequency bands, resulting in the formation of amulti-band mesh network.

A procedure for dual-band mesh entry via D-band is described in thefollowing. A newly joining MSTA may activate its D-band receiver andlisten for beacons, using for example a quasi-omni antenna pattern.Dual-band capable MSTAs may transmit D-band beacons that may include anyof the following information about O-band mesh: O-band capable; O-bandchannel number; beacon interval; capability; supported rates; mesh ID;mesh configuration; mesh awake window; beacon timing; MCCAOPadvertisement overview; MCCAOP advertisement; and/or mesh channel switchparameters. The above O-band related information may be included in asubsequent message exchanged between the new MSTA and the existing MSTAin D-band, such as via a probe request message and a probe responsemessage. This may allow the beacon contents to be reduced.

Upon receiving a D-band beacon, the new MSTA may perform BF training andD-band association or mesh peering with the discovered dual-band capableMSTA. Similarly, BF training and association or mesh peering actions maybe completed with each discovered D-band MSTA.

After completing D-band mesh peering, the new STA may switch to theO-band and send a mesh peering request frame addressed to an existingSTA that was advertised as dual-band capable in the received D-bandbeacons. The new STA may not perform O-band scanning (active orpassive), because it may already have all the information it needs forthe peering request from D-band messages.

Alternately, the dual-band capable new MSTA may perform O-band meshpeering with one or more discovered dual-band capable MSTAs immediatelyafter completing D-band mesh peering, without waiting to complete D-bandmesh peering with all MSTAs in D-band. Therefore, the new STA mayperform O-band mesh peering with a previously discovered dual-bandcapable mesh STA, while simultaneously proceeding with D-band meshpeering with another STA.

The new MSTA may perform O-band mesh peering with other dual-bandcapable MSTAs, with which it has previously performed D-band meshpeering. For example, the new MSTA may perform O-band mesh peering withother MSTAs that were not discovered during scanning in D-band. This mayoccur due to any of the following reasons: the MSTAs may not bedual-band capable; and or the MSTAs are reachable in O-band, but not inD-band. Once mesh peering is completed in all supported bands, the newMSTA may start transmitting beacons in some or all of the bands in whichit operates in order for other MSTAs to discover the mesh network. TheD-band beacons may also include information for other bands supported bythe MSTA.

FIG. 5 is a diagram of an example 802.11s beacon frame body 500. The802.11s beacon frame body 500 may include, but is not limited to, any ofthe following elements pertaining to 802.11s information: mesh ID 502,mesh configuration 504, mesh awake window 506, beacon timing 508, MCCAOPadvertisement overview 510, MCCAOP advertisement 512, and/or meshchannel switch parameters 514. Any of the elements 502-514 may alsoinclude 802.11ad information. The order numbers may be from the IEEE802.11 2012 specification, for example. For example, beacon timing 508may include 802.11ad beacon transmit time, the MCCAOP advertisementoverview 510 may include 802.11ad advertisement overview, and the MCCAOPadvertisement 512 may include an 802.11ad advertisement.

FIG. 6 is a diagram of an example MCCA Setup Request Frame 600. The MCCASetup Request Frame may include, but is not limited to, any of thefollowing elements for 802.11s information: category 602; mesh action604; and MCCAOP setup request element 606. The elements 602-606 mayinclude 802.11ad information. For example, MCCAOP setup request element606 may include 802.11ad scheduling information.

FIG. 7 is a diagram of an example MCCA advertisement element 700. TheMCCA advertisement element 700 may include, but is not limited to, anyof the following 802.11s information: element ID 702; length 704;advertisement set sequence number 706; MCCAOP advertisement elementinformation 708; TX-RX periods report 710; broadcast periods report 712;and/or interference periods report. In an example, the TX-RX periodsreport 710, broadcast periods report 712 and/or interference periodsreport 714 may contain 802.11s and/or 802.11ad information.

As discussed above, the transmission range for different frequencybands, such as the 60 GHz band and the 5 GHz band (or sub-1 GHz band),may be different. FIG. 8 is a diagram of example dual band mesh network800 showing transmission ranges for 60 GHz and 5 GHz. The mesh network800 includes MSTAs 802, 804 and 806. In the example of FIG. 8, thebeamformed 60 GHz transmission range may be longer than the 5 GHztransmission range from the perspective of MSTA 802. The followingexample procedures describe how an MSTA could discover another MSTA via802.11ad frames that is not in the range of 802.11s transmission.

FIG. 9 is a signaling diagram of an example neighbor STA assisted802.11ad link establishment procedure 900 using GPS information. In theexample of FIG. 9, MSTA 902 is seeking to join the network includingMSTAs 904 and 906, and may proceed with either active or passive 802.11sscanning. As shown in FIG. 9, the black arrows represent 802.11ssignaling, and the grey arrows represent 802.11ad signaling.

MSTA 902 may initiate association with the network by listening to802.11s beacons, 908. In an example, MSTA 902 may receive the 802.11sbeacon from MSTA 904 and proceed with mesh peering procedures, asdescribed above. MSTA 904 may inform MSTA 902 by sending a statusmention that may include, but is not limited to, any of the followinginformation: 802.11s and/or 802.11ad TX-RX reports, interference reportsand (e.g., GPS) location information if it is available. If no 802.11sbeacons are detected for a predetermined duration, MSTA 902 may send aprobe frame (not shown) to trigger association procedures. According toan example, MSTA 902 and MSTA 904 may have already had associationprocedures in D-band and/or O-band links in a previous interval (notshown), and hence may be in connected mode.

After the association procedure is completed, MSTA 902 may establishconnection with all available neighbor MSTAs from which it is able todetect 802.11s beacons. Then, MSTA 902 may send an advertisement message914 to its neighbors regarding, for example, its neighbor IDs based onan 802.11s connection and or GPS information. For example, theadvertisement message 914 may be an MCCA advertisement overview frame.

In one example, GPS information may be available to the MSTAs 902, 904and 906. In case MSTA 904 identifies that MSTA 902 and MSTA 906 are notconnected via 802.11s, where location information of MSTA 904 and MSTA902 could be used whether they are capable of establishing connection in802.11ad, then the following procedure may be followed. MSTA 904 maysend a message 916 to MSTA 902 regarding 802.11ad SLS scheduling forMSTA's 904 neighboring STA 906. This may include scheduling informationof MSTAs that are not connected to MSTA 902 via 802.11s but are one-hopneighbors of MSTA 904, such as MSTA 906. With the SLS schedulingavailable, the MSTAs may perform directional TX SLS 918 and RX SLS 920in order to identify the best TX and RX beams corresponding to MSTA 902.MSTA 906 may send a beam ID feedback message 922. MSTA 906 may send thefeedback message 922 to MSTA 902 via D-band signaling to include thebeam ID of the received D-band beam with highest SNR in the received SLS922 carried out by MSTA 902.

In an alternative example, no GPS information may be available to theSTAs. With no GPS information available and no 802.11s neighbor STA IDinformation obtained from the associated STAs, the MSTAs may employpassive listening of 802.11ad beacon transmissions by the joining MSTA.During idle scheduling intervals of the MSTAs (e.g., no transmission orreception is scheduled and no known TBTT from the neighbor STAs), theMSTAs may switch to the listening mode via receive SLS. If an 802.11adbeacon is detected, e.g., above RSSI threshold during the idle periods,the MSTA initiate discovery procedures with the knowledge of beacontransmission time and RSSI.

Once the newly joining MSTA A and a two-hop neighbor MSTA are connectedvia 802.11ad frames, these MSTAs may pursue mesh peering stage over802.11ad. In other words, these MSTAs may transmit and receive data over60 GHz, and hence may be part of the hybrid mesh network.

802.11s MCCA scheduling may be based on omni-directional transmission.In an example, using the spatial separation among the neighbor MSTAtransmissions, an 802.11ad scheduling mechanism may be used. Themechanism may include information from the neighbors that may determinethe interfering neighbor list. A combination of the interfering neighborlist along with the TX-RX time report may be used to obtain spectrallyefficient scheduling among the MSTAs.

Following the mesh MSTA neighbor discovery, mesh peering and 802.11adbeamforming stages, as described above, the MSTAs may establishdirectional beams with their neighbors. Hence, the MSTAs may havebeamformed 802.11ad links with their neighbors along with the 802.11sconnection. In order to identify potentially interfering MSTAs, theMSTAs may go through an interference table formation procedure todetermine the interference power due to neighbor MSTAs transmission.

FIG. 10 is a signaling diagram of an example interference measurementprocedure 1000 from the perspective of a measuring MSTA 1002. Thefollowing describes an example of interference table formation. Ataction 1012, the measuring MSTA 1002 identifies the scheduled TXOP ofMSTAS 1004, 1006, 1008 and opportunistically uses the time slots thatare allocated by other MSTAs 1004, 1006, 1008, for their correspondingtransmission and reception. These slots may already be known to themeasuring MSTA 1002 based on MCCAOP advertisement overview elements 1010received from the neighboring MSTAs 1004, 1006, 1008. From the MCCAOPadvertisement overview element 1010, the measuring MSTA 1002 mayidentify which MSTA allocates the channel at a given scheduling intervalat 1012.

During interference measurement 1014, the MSTA 1002 may switch itsreceive beams assigned to different neighbors and thus measure theinterference at each receive beam. For example, the interferencemeasurement 1014 may be RSSI based or may involve decoding of thereceived signals. In case the MCCAOP duration allocated by a neighborMSTA is not sufficient to complete the measurement 1014 for all receivebeams, the measuring MSTA 1002 may resume the measurement 1014 in afuture MCCAOP allocated for the same neighbor MSTA(s) 1004, 1006, and/or1008.

In one example, the measurement 1014 may be carried out for two-hopneighbors transmission. In this case, using MCCAOP interferenceadvertisement set, the MSTA 1002 may identify TXOP for the 2-hopneighbors. These slots may be utilized for the measurement campaign bysequentially measuring the interference at the measuring MSTA 1002.

In another example, the measuring MSTA 1002 may send a measurementrequest message (not shown) to the neighbor MSTAs (e.g., MSTAs 1004,1006, and/or 1008) that it wishes to make the measurement. The MSTA thatreceives this request (responder MSTA) may schedule a measurementcampaign to sequentially transmit towards its neighbors whereas themeasuring MSTA 1002 may perform interference measurement due to thesebeams. The responder MSTA may determine available TXOPs for sequentialtransmission. These interference measurement slots may be feedback tothe measuring MSTA 1002 via an MCCA advertisement overview.

After the measurement campaign 1014, the MSTAs 1004, 1006, 1008, maydetermine the received interference due to one-hop and two-hop neighborsand may identify which MSTAs and their corresponding transmission createabove the threshold interference.

The measuring MSTA may inform the other MSTAs 1004, 1006, 1008 of theinterference level via interference messages 1016, for example EX_INTmessages, so that the MSTAs 1004, 1006, 1008, may identify the neighborMSTAs with which they create over-the-threshold interference. Forexample, the EX_INT messages 1016 may be carried via management framesusing 802.11s links or may be transmitted directly via 802.11ad datalinks. Then, each MSTA 1004, 1006, 1008, may create an interferencetable 1018, 1020, 1022, respectively, which determines the MSTAs thatthey create interference associated with each of its transmit beam.

According to another embodiment, data slots may be scheduled in 802.11adlinks. For a data scheduling request, the requestor MSTA may send anMCCA setup request to the responder MSTA, for example using 802.11sframes and/or 802.11ad frames. The requestor MSTA may consider the anyof the following inputs to determine the available TXOP to be requestedfrom the responder MSTA: an MCCA advertisement report, a TX-RX report,an interfering times report, and/or an interference table.

The requestor MSTA may utilize spatial transmission by considering theinterference table and identifying non-interfering scheduling slots.Then, the requestor MSTA may send an MCCAOP setup request message to theresponder MSTA with the scheduling slots to be requested. The responderMSTA may accept or reject the request by checking its own MCCAadvertisement report and interference table. The responder MSTA mayfeedback an MCCAOP reply message where it may accept the reservationrequest or it may reject it and suggest a new set of scheduling slots.

According to an embodiment, directional MCCA scheduling may be QoSbased. Procedures and mechanisms for a 802.11s TXOP scheduling stage aredescribed herein, which may incorporate the QoS requirements of the MSTAtraffic packets. MSTAs may be connected via 802.11s and beamformed802.11ad signals, as described above. The requestor and responder MSTAsmay exchange information, including for example TXOP and/or TBTT, via802.11s based MCCA advertisement frames and/or via 802.11ad baseddirectional MCCA advertisement frames. The requestor MSTA may alsoinclude the BSR in the MCCA advertisement in 802.11s packets and/or802.11ad packets. In one example, 802.11s based advertisement packetsmay be transmitted in a broadcast fashion so that multiple neighbors mayhear the transmission simultaneously to increase spectral efficiency.The responder MSTA may collect the BSR from the peer MSTAs within apredefined time period. The responder may allocate the MCCAOPs (e.g., in60 GHz) based on the BSR of the neighbor MSTAs. The responder maybroadcast the MCCA reply frames in 802.11s and/or 802.11ad frames. Inone example, if 802.11s is used for the advertisement frame, then theadvertisement frame may be simultaneously received by multiple requestorMSTAs due to broadcasting.

According to another embodiment, adaptive MCCA access fraction (MAF) maybe based on QoS constraints. The MAF may be defined as the ratio of timereserved for MCCAOPs in the delivery traffic indication message (DTIM)interval for a particular MSTA to the duration of the DTIM interval. Themaximum value for the MAF at an MSTA may be limited by a parametercalled MAFLimit. The MAF and MAFLimit may be used to limit the use ofMCCA by a particular MSTA. This MAF mechanism may be seen as a tool toavoid starvation of MSTAs that are not MCCA capable.

MAF may be maintained by taking into account QoS. For example, an MSTAmay maintain MAF values specific to each configured QoS class, which maybe referred to as QoS Access Fraction (QAF). QAF of a QoS class may bedefined as the ratio of time reserved for MCCAOPs for that particularQoS in the DTIM interval for a particular MSTA to the duration of theDTIM interval. A limit referred to as QAFlimit may be associated witheach QAF that may restrict the total MCCAOPs used up by the traffic froma particular QoS. For example, for a particular QoS the QAF≤QAFLimit mayalways be true.

MSTAs may be configured with an Aggregate Access Fraction (AAF)parameter that determines the total time reserved for MCCAOPs for allthe configured QoS classes. The maximum value for the AAF for an MSTAmay be limited by a parameter called AAFLimit. Each QAFLimit for eachQoS class may be configured up to a max value of AAFLimit. For example,the MSTAs may treat the MAF (e.g., as defined in IEEE 802.11s) as AAFand MAFLimit as AAFLimit. In summary, any of the following equations mayapply to MAF:Σ_(i=0) ^(maxQosClass)QAF(i)=AAF≤AAFLimit  Equation 1QAF(i)≤QAFLimit(i)∀i∈(0,maxQosClass−1)  Equation 2QAFLimit(i)≤AAFLimit∀i∈(0,maxQosClass−1)  Equation 3where maxQosClass refers to the maximum number of QoS classes supportedby the system.

Examples of signaling QAF parameters are described herein. The MSTA mayadvertise the QAF parameters in the MCCAOP advertisement frames. In oneexample, the QAF parameters may be band specific. The MSTA may broadcastthe band specific MCCAOP advertisement frame. The band specific MCCAOPadvertisement frame may carry the QAF specific to that band. The MSTAmay also request MCCAOPs specific to a particular QoS by including, inthe MCCAOP setup request, the QoS identifier for the MCCAOP reservation.

QoS aware MCCAOP setup procedures are described herein. According to anembodiment, the MCCA owner may setup a new MCCAOP, such that conditionsin the 802.11s specification are satisfied. In this case, the MCCAOPowner may determine the MCCAOP reservation based on QAF parameters. Forexample, an MCCAOP owner may consider one or more of the followingcriteria: the MCCAOP reservation for a particular QoS may not cause thecorresponding QAF value to exceed QAFLimit either for the MCCA owner orfor the neighbor MSTAs; and/or the MCCAOP reservation for a particularQoS may not cause the AAF value to exceed the configured AAFLimit,either for the MCCA owner or for the neighbor MSTAs.

Upon receiving a MCCAOP Setup request, an MCCAOP responder MSTA, inaddition to conditions mentioned in IEEE 802.11s specifications, mayverify any of the following conditions: the MCCAOP reservation for therequested QoS may not cause the corresponding QAF value to exceedQAFLimit either for the MCCA responder or for the neighbor MSTAs; and/orthe MCCAOP reservation for the requested QoS may not cause the AAF valueto exceed the configured AAFLimit either for the MCCA responder or forthe neighbor MSTAs.

The following preemption procedures may be used. According to anembodiment, the MCCAOP owner and/or the MCCAOP responder may accommodatenew MCCAOP reservation requests by preempting one or more of theexisting MCCAOPs between them. In another embodiment, the preemptionprocedure may involve MSTAs which are neither MCCAOP owner nor MCCAOPresponder.

The MSTAs may follow any of the following preemption rules. According toa preemption rule, if the new MCCAOP reservation for a particular QoSdoes not cause corresponding QAF to exceed QAFLimit and does not causethe AAF to exceed AAFLimit, then the MCCAOP setup may be consideredsuccessful.

According to another preemption rule, if the new MCCAOP reservation fora particular QoS does not cause QAF to exceed QAFLimit, but causes AAFto exceed AAFLimit, then any of the following actions may be taken. Forexample, MCCAOPs of lower than the requested QoS may be re-sized (i.e.,reduced in size or decrease the periodicity) until the AAF becomes lessthan AAFLimit. In this case, MSTAs may use new MCCAOP Setup updatemessages to resize the existing MCCAOPs, or, the MSTAs may tear down theMCCAOPs and trigger a new MCCAOP setup message with modified MCCAOPsize.

In another example, MCCAOPs of lower than the requested QoS may be torndown until AAF becomes less than AAFLimit. In another example, theresizing or purging decisions may be made based on minNQAF and minNAAFparameters. minNQAF is the minimum Access Fraction guaranteed for aparticular neighbor for a specific QoS. minNAAF is the minimum AggregateAccess Fraction for a particular neighbor for all QoSes. These neighborspecific QAF parameters may be negotiated during mesh peering procedureor may be modified during MCCAOP setup/response procedures.

In another example, each MSTA may be configured with minOQAF and minOAAFparameters. The resizing or purging decisions may consider minOQAF andminOAAF. The minOQAF is the minimum Access fraction guaranteed for theown traffic with a particular QoS generated by the MSTA itself or forthe traffic addressed to the MSTA. The minOAAF is the minimum AggregateAccess Fraction for all the traffic generated by or addressed to theMSTA. For example, these values may be zero for a pure relay MSTA.

In another example, each MSTA may be configured with minFQAF and minFAAFparameters. The resizing or purging decisions may consider minFQAF andminFAAF. Where minFQAF is the minimum Access fraction guaranteed for thetraffic belonging to specific QoS forwarded via this particular MSTA.minFAAF is the minimum Aggregate Access Fraction for all the trafficforwarded by the MSTA. If the above actions would not make AAF less thanAAFLimit, then the new MCCAOP reservation may fail and procedures, suchas those defined in IEEE 802.11s, may be performed.

According to another preemption rule, if the new MCCAOP reservation fora particular QoS causes QAF to exceed QAFLimit, then the new MCCAOPreservation may fail and appropriate procedures, for example inaccordance with IEEE 802.11s, may be performed.

Buffer status advertisement procedures are described herein. MSTAs mayperiodically advertise their QoS specific buffer status to their meshneighborhood. For example, the buffer status may capture the averageoccupancy for each logical buffer associated to different QoS classes.The buffer status may be advertised in a separate advertisement messageor may be combined with MCCAOP advertisement message, for example. TheMCCAOP owner may send the buffer status specific to the MCCAOPresponder. In other words, the buffer status may provide the status ofqueues specific to the responder. The MCCAOP owner may use D-bandtransmissions to send such responder-specific buffer status reports. Inan example, the MSTA specific buffer status may be sent in MCCAOP setupRequest.

Each potential MCCAOP owner may track the buffer status advertisementfrom its mesh peers in some or every DTIM interval. Buffer status may bespecific to bands, for example an MSTA may advertise the buffer statusfor O-band and D-band separately. This may be used if the meshneighborhood has MSTAs which are either O-band or D-band capable, butnot both. The MCCAOP owner may use the buffer status advertisement frompeer MSTAs to prioritize the MCCAOP responder. For example, the MCCAOPowner may use the multi-band buffer status to prioritize the MCCAOPreservation in a particular band. The MCCAOP owner may prefer thecandidate MSTAs with larger queue differentials, subject to inputs fromthe routing function.

Table 1 is an example buffer status advertisement element format, asdescribed above, and may include, but is not limited to, any of thefollowing elements: element ID; length; number of band list; and/ormulti-band buffer status list. Table 2 is an example multi-band bufferstatus element format, as described above, and may include, but is notlimited to, any of the following elements: band ID; channel number;number of QoS list; and/or multi-QoS buffer status list. Table 3 is anexample multi-QoS buffer status element format, as described above, andmay include, but is not limited to, any of the following elements: QoSID; instantaneous buffer length; and/or average buffer length.

TABLE 1 buffer status advertisement element format Element ID LengthNumber of Multi-band Band list Buffer status list

TABLE 2 multi-band buffer status element format Band ID Channel Numberof Multi-QoS Number QoS List Buffer status list

TABLE 3 multi-QoS buffer status element format QoS ID InstantaneousAverage Buffer length Buffer length

An MCCAOP update procedure including QoS and multi-band is describedherein. An MCCAOP update message may be used either by MCCAOP responderor by the MCCAOP owner to modify the existing MCCAOP reservation withouthaving to tear down and trigger a new setup procedure. An MCCAOP updateprocedure may be triggered as a result of preemption due to a QoS awareMCCA setup procedure. An MSTA may choose to trigger the update procedureinstead of a teardown and setup procedure if the MCCAOP reservationre-uses parts of old reservation time period and/or is in the same band,and/or if any of the following conditions are true:

New MCCAOP Offset>=Old MCCAOP Offset; and/or

New MCCAOP offset<(Old MCCAOP offset+Old MCCAOP Duration); and/or

New MCCAOP duration<Old MCCAOP duration; and/or

New MCCAOP periodicity<=Old MCCAOP periodicity

In one example, the MSTA may use the MCCAOP update element to requestthe peer MSTA to update the existing MCCAOP reservation. Table 4 is anexample MCCAOP update request element format, and may include, but isnot limited to, any of the following elements: element ID; length; CCAOPreservation ID; and/or updated MCCAOP reservation. The filed updatedMCCAOP reservation may carry the new MCCAOP offset, new MCCAOP durationand new MCCAOP periodicity. Table 5 is an example Updated MCCAOPReservation and may include, but is not limited to, any of the followingelements: band ID+channel number; QoS ID; new MCCAOP duration; newMCCAOP periodicity; and/or new MCCAOP offset.

TABLE 4 MCCAOP update request element format Element ID Length MCCAOPUpdated MCCAOP Reservation ID Reservation

TABLE 5 updated MCCAOP reservation Band ID + QoS ID New New New channelMCCAOP MCCAOP MCCAOP number Duration Periodicity Offset

The MSTA may relocate the high priority MCCAOP reservation to anexisting low priority MCCAOP reservation time period. In particular, therelocated MCCAOP reservation may use parts of one or more low priorityQoS MCCAOP reservation time periods. The MSTA may relocate the highpriority MCCAOP reservation to another band, which may override anexisting low priority QoS MCCAOP reservation time period in the targetband.

According to an embodiment, MCCAOP setup message may address QoS andmultiband. An MCCAOP reservation may specify a schedule for frametransmissions. The time periods scheduled for frame transmissions in thereservation are called MCCAOPs. The schedule may be set up between anMCCAOP owner and one (for individually addressed frames) or more (forgroup addressed frames) MCCAOP responders. A dual band capable MSTA mayprovide the requested band information in the MCCAOP setup requestmessage, for example in an additional field (e.g., band ID field), whichmay specify the preferred band and/or channel information. The Band IDfield may be one octet in length and may be defined as in the exampleband ID field format shown in Table 6.

TABLE 6 band ID field Band ID value Meaning 0 TV white spaces 1 Sub-1GHz (excluding TV white spaces) 2 2.4 GHz 3 3.6 GHz 4 4.9 and 5 GHz 5 60GHz 6-255 Reserved

In addition to the band ID field, the MCCAOP owner may request thespecific channel in which the MCCAOP is requested. For example, theMCCAOP owner may add the operating class and/or the specific channelnumber in the MCCAOP setup request message.

The MCCAOP owner may consider the capabilities of the MCCAOP responderbefore requesting specific band/channel combinations in the setuprequest message. The MCCAOP owner may choose to ignore the channelnumber in the setup request, in which case the MCCAOP responder maychoose any channel in the requested band to allocate the MCCAOP. Inanother example, MCCAOP owner may include more than one band/channelcombination in the MCCAOP setup request message.

According to an embodiment, MCCAOP allocation may be QoS specific. A QoSaware MSTA may include a QoS identifier in the MCCAOP setup requestmessage. The QoS information may enable the service prioritization bythe MSTAs and may serve as an input for preempting low priority serviceswhen a request for high priority service is made using MCCAOP setuprequested. In one example, the QoS identifier may be mapped to theaccess category index (ACI). Table 7 is an example QoS to ACI indexmapping, where: AC_BE is access category for best effort, AC_BK is theaccess category for background, AC_VI is the access category for video,and AC_VO is the access category for voice.

TABLE 7 QoS to ACI index mapping ACI AC Description 00 AC_BE Best Effort01 AC_BK Background 10 AC_VI Video 11 AC_VO Voice

The MSTAs (MCCAOP owner, MCCAOP responder) transmitting data during theMCCAOP reservation, which was setup using explicit QoS request, mayfollow the following prioritization order. For example, the databelonging to the QoS for the corresponding MCCAOP reservation may beprioritized. If there is additional space left in the MCCAOPreservation, the MSTA may apply one or more of the following rules, inany combination. According to a rule, the MCCAOP may be truncated bytransmitting a CF-End frame or QoS Null frame. According to anotherrule, the data belonging to the next high priority QoS class addressedto the receiving MSTA for the current MCCAOP reservation may be mapped.According to another rule, the data belonging to the QoS which hashighest buffer backlog may be mapped. According to another rule, thedata belonging to the QoS which has lowest QAF may be mapped.

Table 8 is an example MCCAOP setup request element format including, butnot limited to: element ID; length MCCAOP reservation ID; and/or MCCAOPreservation. Table 9 is an example MCCAOP Setup Request element withBand and QoS information including, but not limited to: element ID;length; QoS ID; band ID; channel number; MCCAOP reservation ID; and/orMCCAOP reservation. Table 10 is an example MCCAOP Setup Request elementwith multi-band request including, but not limited to: element ID;length; QoS ID; number band list; and/or multi-band reservation list.Table 11 is an example multi-band reservation list including, but notlimited to: band ID; channel number; MCCAOP reservation ID; and/orMCCAOP reservation.

TABLE 8 MCCAOP setup request element format Element ID Length MCCAOPMCCAOP Reservation ID Reservation

TABLE 9 MCCAOP setup request element with band and QoS informationElement Length QoS Band Channel MCCAOP MCCAOP ID ID ID numberReservation ID Reservation

TABLE 10 MCCAOP setup request element with multi-band request Element IDLength QoS ID Number Multi-band band list reservation list

TABLE 11 multi-band reservation list Band ID Channel MCCAOP MCCAOPnumber Reservation ID Reservation

Upon receiving the MCCAOP setup request message, the MCCAOP respondermay perform any of the following actions. For example, the reservationfor at least one band if multi-band information is present) may notoverlap with the neighborhood MCCAOP periods for that particular band.The reservation may not cause MAF limit to be exceeded for itself or itsneighbor MSTAs. The reservation may not cause any of the QAF limits tobe exceeded, as described above.

If two or more bands satisfy the above criteria, the MCCAOP respondermay perform any combination of the following actions: choose the bandfor which the MAF (or QAF) of the mesh neighborhood for that particularQoS is lowest; choose the band where the interference metric is thelowest; choose the band with lowest buffer backlog for that particularQoS; choose more than one band and allow the traffic for the particularQoS to be split between those bands; and/or choose the band in the orderof preferred band configuration provided by the SME interface. Table 12is an example MCCAOP setup reply that may include, but is not limitedto: element ID; length; MCCAOP reservation ID; MCCA reply code; and/orMCCAOP reservation.

TABLE 12 MCCAOP setup reply Element ID Length MCCAOP MCCA Reply MCCAOPReservation ID Code Reservation

If a single band does not satisfy the MCCAOP reservation requirementsrequested by the MCCAOP owner, for example due to MAF or QAF limits, theMCCAOP responder may choose to split the allocation across two bands.The MCCAOP responder may still obey the rules for band parameters (e.g.,MAF, QAF) for each part of individual allocation. In this case, theMCCAOP responder may send an MCCAOP setup reply with the multi-bandinformation in a list of MCCAOP reservation fields. The MCCAOPreservation list may capture different parts of the allocation withassociated band/channel information. Table 13 is an example MCCAOP setupreply element format with multi-band information that may include, butis not limited to: element ID; length; number reservation list; and/ormulti-band reservation list.

TABLE 13 MCCAOP setup reply element format with multi-band informationElement ID Length Number Multi-band reservation list reservation list

According to an embodiment, MCCAOP advertisement may address QoS andmulti-band. For example, each MSTA may advertise its MCCAOPadvertisement set to its neighbor MSTAs. The advertisement set mayinclude own TX-RX reservation, reservations in the neighborhood that maycause interference and the broadcast reservations. To enable QoS awareMCCAOP reservation, the MSTA may advertise the QoS class of each MCCAOPreservation that belongs to the advertisement set. An MCCAOP owner mayconsider the QoS information of each MCCAOP reservation advertised byresponder and the neighborhood to make preemption decisions.

The MCCAOP reservations advertised in the MCCAOP advertisement framesmay include an additional QoS identifier. In one example, the QoSidentifier may be appended to MCCAOP reservation field. Table 14 is anexample MCCAOP reservation field that may include, but is not limitedto: MCCAOP duration, MCCAOP periodicity, MCCAOP offset, and/or QoSidentifier. A QoS identifier may be added to any or all the reports inthe advertisement set, including TX-RX report, broadcast report and/orinterference report.

TABLE 14 MCCAOP reservation field MCCAOP MCCAOP MCCAOP QoS durationPeriodicity Offset identifier

MCCAOP advertisement may also carry the in addition to MAF parameters toenable QoS aware MCCAOP reservation procedures. In one example, the QAFparameters may be added to MCCAOP advertisement overview element. Table15 is an example MCCAOP Advertisement overview element format thatincludes, but is not limited to: element ID, length, advertisementsequence number, flags, MCCA access fraction, MAF limit, QAF length, QAFlist, band ID+channel number, and/or advertisement elements bitmap.Table 16 is an example QAF list that includes, but is not limited to:QoS ID, QoS access fraction, and/or QAF limit.

TABLE 15 MCCAOP advertisement overview element format Element LengthAdvertisement Flags MCCA MAF QAF QAF Band ID + Advertisement ID SequenceAccess Limit length List Channel Elements Number Fraction number Bitmap

TABLE 16 new QAF list QoS QoS Access QAF Limit identifier Fraction

An MSTA may broadcast the MCCA advertisement frame for a set of QoStriggers, in addition to other triggers, as described in the following.For example, a frame broadcast may be triggered when the MCCAOPresponder accepts a new MCCAOP reservation and the MCCAOP responder maychange the QAF of one or more QoS class (e.g., directly due to newMCCAOP reservation, or indirectly due to the preemption of existingMCCAOP reservation). In another example, a frame broadcast may betriggered when the MCCAOP owner receives confirmation for MCCAOPreservation from the MCCAOP responder that changes the QAF of one ormore QoS classes. In another example, a frame broadcast may be triggeredwhen the MSTA receives MCCAOP update frame that preempts or changes theMCCAOP reservation belonging one or more QoS classes. In anotherexample, a frame broadcast may be triggered when the MCCAOP responderreceives an explicit MCCAOP teardown request or performs an implicitteardown that changes the value of the QAF. The same applies for theMCCAOP owner which triggered the teardown request.

In an example, the MSTA may advertise only the MCCAOP reservations thatare modified by broadcasting the appropriate bitmaps in theadvertisement overview element. The MSTA may also choose to selectivelybroadcast the QAF parameters which are modified. In another example, theMSTA may advertise the status of multiple bands, for example in a commonpre-configured band (e.g., O-band) or advertisement message such thateach band may carry the status of that specific band.

According to an embodiment, an MCCAOP advertisement request message mayaddress QOS and multi-band. An MSTA may transmit an MCCAOP advertisementrequest frame to request all the MCCAOP advertisement elements or aselected subset of MCCAOP advertisement elements from the neighbor peerMSTA. In one example, the MSTA may request the status of a specific timeperiod in the DTIM interval, whether it is reserved or free. Forexample, the specific time period may be requested by the MCCAOPreservation report field. The responding MSTA may provide the status ofthe specific time period and it may specify which QoS class for thespecific time period being used. In case two or more MCCAOPs cover therequested time period, then a list of QoS classes and the conflictingMCCAOP reservations may be provided.

In another example, the requesting MSTA may specifically query thestatus of a time period in a particular band of interest. For example,this may be specified by adding a list of band IDs to the MCCAOPadvertisement request, for which the status is requested. Table 17 is anexample MCCAOP advertisement request frame format that may include, butis not limited to: element ID; length; advertisement sequence number;flags; MCCA access fraction; MAF limit; QOA length; band list length;band ID+channel list; MCCAOP reservation report; and/or advertisementelements bitmap. Table 18 is an example MCCAOP reservation report fieldthat may include, but is not limited to: number of MCCAOP reservation;and/or MCCAOP reservation 1 . . . MCCAOP reservation n.

TABLE 17 MCCAOP advertisement request frame Element Length AdvertisementFlags MCCA MAF QAF . . . ID Sequence Access Limit length Number Fraction. . . QAF Band Band MCCAOP Advertisement List list ID + reservationElements length channel report Bitmap list

TABLE 18 MCCAOP reservation report field Number of MCCAOP MCCAOP . . .MCCAOP reservation reservation 1 reservation n

According to an embodiment, QoS based MCCAOP reservation procedures mayinvolve multiple MSTAs. The addition of a QoS ID in the MCCAOPreservation field, as described above, may allow MCCAOP reservationsbased on QoS considerations spanning multiple MSTAs. This may involvecommunication between an MSTA that wants to set up a new MCCAOP for ahigher QoS class than an existing MCCAOP between another pair ofneighboring MSTAs. This may result in teardown or modification ofexisting lower QoS MCCAOP and setting up of a new MCCAOP with higherQoS. An example QoS based MCCAOP reservation procedure may be asfollows.

The MSTA wanting to establish a new MCCAOP with a higher QoS class maysend a MCCAOP advertisement request frame to collect MCCAOPadvertisements from its neighbors, or may listen passively to collectthe MCCAOP advertisements. In either case, the MSTA may determine thetransmission schedule and the associated QoS classes of alltransmissions. The MCCAOP reservation field described above may be usedhere. If the MSTA determines that the MCCAOP schedule between anotherMSTA pair with lower QoS class occupies the only time slots available toit, then the MSTA may send a request to one of the MSTAs involved in theexisting MCCAOP to vacate the channel at those time. Accordingly, theMSTA may send a MCCAOP setup request frame to the neighbor MSTA that ispart of the existing MCCAOP, either as owner or responder.

The MCCAOP reservation ID field may contain the value 255. This mayindicate to the MSTA involved in the existing MCCAOP, that this is aMCCAOP modification request. The MCCAOP reservation field may containthe timing information related to the proposed new MCCAOP with higherQoS class. This may overlap with multiple existing MCCAOPs with thetarget MSTA as a participant. Upon receiving the MCCAOP setup requestfrom the requesting MSTA with reservation ID field value of 255, thetarget MSTA may determine if its existing MCCAOP(s) may be modified. Ifthe target MSTA determines that modification is possible, then thetarget MSTA may send a MCCAOP setup request or MCCAOP teardown frame toits counterpart in the affected MCCAOP.

When the target MSTA receives confirmation from its counterpartregarding change in MCCAOP, either as changed advertisement element or amesh setup response frame, it may send a MCCAOP setup reply to therequesting MSTA. In the transmitted MCCAOP setup reply, the target MSTAmay set the value of reservation ID field to 255, such as in thereceived MCCAOP setup request. The MCCA reply code field may be set tothe value that determines the decision, whether the MCCAOP setup requestis granted or not.

The MCCAOP reservation field may be present. When present, it mayrepresent an alternative to the MCCAOP reservation specified in theMCCAOP setup request message. When the MCCAOP reply code is set to 1(i.e., Reject: MCCAOP reservation conflict), the MCCAOP reservationfield may be present. When the MCCAOP Reply Code is set to other values,the MCCAOP reservation field may not be present.

When the requesting MSTA receives the MCCAOP setup reply message fromthe target MSTA with reply code value indicating acceptance, or a MCCAOPreservation that is acceptable, the requesting MSTA may send a MCCAOPsetup request message to the intended responder of the new MCCAOP. Theresponder may respond with MCCAOP setup reply message indicating itsacceptance, and the new MCCAOP may become operational. The new schedulemay be included in future MCCAOP advertisement elements transmitted bythe two MSTAs either as part of beacons or MCCAOP advertisement frames.The MCCAOP advertisement messages may be broadcast on O-band fortransmission efficiency. Data transmissions may occur in D-band.

Additionally, a new Long MCCAOP Reservation field may be used toidentify possibilities for simultaneous directional transmissionopportunities in D-band. Table 19 is an example of a Long MCCAOPReservation field that may include, but is not limited to: MCCAOPduration; CCAOP periodicity; MCCAOP offset; MCCAOP QoS ID; MCCAOPreservation ID; and/or MCCAOP owner ID.

TABLE 19 long MCCAOP reservation field MCCAOP MCCAOP MCCAOP MCCAOPMCCAOP MCCAOP Duration Periodicity Offset QoS ID Reservation Owner ID ID

During an interference measurement procedure, a MSTA may associateobserved signal power levels with a pair of MCCAOP Owner ID and MCCAOPReservation ID, which may uniquely identify a transmission direction ata neighboring MSTA. Thereafter, by examining the MCCAOP Owner ID andMCCAOP Reservation ID in received MCCAOP Advertisement elements duringregular data transmissions, the MSTA may determine if the advertiseddirectional transmission will interfere with any of its MCCAOPs/neighbortransmissions. If an MCCAOP/neighbor is identified that is not affectedby the advertised MCCAOP between other neighboring MSTAs, then the MSTAmay schedule a MCCAOP with the identified neighbor to coincide in timewith the other MCCAOP. This may enable concurrent directionaltransmission opportunities.

Hybrid routing procedures for dual-band mesh networks are describedherein. A metric determination may be used for routing in 802.11ad and802.11s based hybrid networks, which may include the informationexchange procedures, and hybrid routing protocol actions. The airtimelink metric may include O-band and D-band metrics. An airtime linkmetric c_(a) for an MSTA A may be defined to incorporate the effect ofinterference due to selecting the corresponding link:

$\begin{matrix}{c_{a} = {\left\lbrack {O + \frac{B_{t}}{r}} \right\rbrack\frac{1}{1 - e_{f}}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

where r is the data rate of test frame size B_(t); and e_(ƒ) is theframe error rate for the test frame.

csd=ƒ(c_(a), int_(sd)). int_(sd) is a factor that may quantify the linksthat cannot be scheduled by neighbor MSTAs due to transmission. csd maydefine an updated airtime link metric to include the effect of linksthat cannot be scheduled as well as the airtime link metric c_(a). Here,ƒ may represent an arbitrary function that inputs c_(a) and int_(sd).int_(sd) may define an indicator function such that int_(sd)=(int_(s),int_(d)) is an OR operation with int_(s) and int_(d) taking binaryunits, 0 or 1. int_(s) may define an indicator which takes the value 1if the source's transmission address to the destination createsinterference at any node pair in the network. Otherwise, it may take thevalue of 0. Similarly, int_(d) may define an indicator that may take thevalue 1 if the destination's transmission addressed to the sourcecreates interference at any node pair in the network. Otherwise, it maytake the value of 0. Hence, based on the values of int_(s) and int_(d),csd may take the value of csd=(0,0)=0; csd:=(0,1):=(1,0):=1,1)=1.

FIG. 11 is a system and signaling diagram of an example multi-bandrouting and scheduling procedure 1100. The dual-band MSTAs shown in FIG.11 include MSTA 1102, MSTA 1104, MSTA 1106, and MSTA 1108. In the 5 GHzband, during TXOP 11101 the transmission from MSTA 1102 to MSTA 1104 mayprevent MSTA 1106 to MSTA 1108 scheduling. For example, withint_(sd)=(ints, intd), the source or s=MSTA 1102, the destination ord=MSTA 1104, then int_(sd)=1, since MSTA 1102 to MSTA 1104 transmissionmay create interference to the MSTA 1106 to MSTA 1108 communication. Onthe other hand, in 60 GHz, the transmission of MSTA A may not preventthe scheduling of any other STAs, hence intd=0. In another example, thereal interference values may be incorporated into the metrics. Forexample, int_(s,1106-1108)=x; int_(d,1106-1108)=y, and so forth, whichmay be utilized in route determination.

FIG. 12 is a diagram of an example mesh link metric report element 1200.The mesh link report element 1400 may include, but is not limited to,any of the following elements: element ID 1202 (e.g., 1 octet); length1204 (e.g., 1 octet); flags 1208 (e.g., 1 octet); airtime link metric1208 (e.g., variable number of octets); and/or band selection 1210(e.g., variable number of octets). In one example, the MSTAs mayexchange test frames in 5 GHz and 60 GHz, and the mesh link metricreport element 1200 may be transmitted in 5 GHz only with a link metricelement 1208. The link metric 1208 may include both bands. In anotherexample, the mesh link metric report element 1200 may be transmitted inboth bands.

The path target MSTA may obtain the path metric via path request (PREQ)frames in 802.11s. The PREQ frames include path metric that may be acombination of O-band and D-band metrics. Each intermediate MSTA thatreceives a PREQ frame may check the path metric in the frame. If themetric is better than the existing one, the MSTA may update its pathinformation to the originator MSTA and may propagate the PREQ to theneighbors. In one example, in dual band, the MSTA may also include a bitsequence (band selection) that denotes whether O-band and/or D-band isselected in updating the path metric. The selection procedure may alsoconsider the interference created as given by int_(sd).

The airtime link metric for 802.11s mesh networks may be designed foroptimum path selection in omni-directional mesh networks. The airtimelink metric c_(a) may be a cumulative metric that reflects the totaltime required to transmit a unit test packet from source to destination.While the metric is sufficient to capture individual link and end-to-endpath metrics for O-band mesh networks, the metric may fail to properlycapture the effects of simultaneous transmissions by directional MSTAs.Thus, additional link metrics and path selection procedures fordirectional mesh networks are described below.

A locally-aware link metric update procedure is described herein. TheHybrid Wireless Mesh Protocol (HWMP) procedure may determine an optimumsource to destination path based on airtime link metric. According to anexample procedure, a source may send a PREQ message with an ID of anintended destination. An airtime link metric value may be included inthe message (e.g., c_(a)=0 initially). A hop count may also be included(initialized to 0).

All MSTAs that receive the PREQ message may forward it on to theirneighbors with following modifications and exceptions. The airtime linkmetric may be updated with the value for the particular link as follows:c _(a)(j)=c _(a)(j−1)+c _(a)  Equation 5where, c_(a)(j) is the updated airtime link metric; c_(a)(j−1) is thevalue in the received PREQ message and c_(a) is the calculated linkmetric for the link from the PREQ source to the current MSTA.

If the MSTA has already forwarded a PREQ message for thesource-destination pair with a smaller airtime link metric within apreceding predetermined duration, the MSTA may drop and may not forwardthe current PREQ message. This may prevent unnecessary forwarding ofpackets with inferior cumulative path metric. If the MSTA already knowsa path to the destination, then it may respond to the PREQ sender with apath response (PREP) message with the cumulative path metric todestination. The PREQ message may not be forwarded towards thedestination in this case.

The destination MSTA may receive multiple PREQ messages from itsneighbors. The destination MSTA may then determine the optimum pathbased on the smallest cumulative airtime link metric. The destinationMSTA may send a PREP message to the MSTA that sent the PREQ message withsmallest metric. The destination MSTA may include the final cumulativemetric calculated by the destination MSTA in the PREP message. The PREPmessage may be relayed back by each MSTA to its previous MSTA with thesmallest cumulative metric at that point. This message may ultimatelyget back to the source and therefore establish the optimum path.

According to an embodiment, a locally-aware link metric update proceduremay capture simultaneous directional transmissions effects. The linkmetric calculations may be modified to account for interference due tosimultaneous transmissions in the vicinity of each MSTA forming apotential path.

MSTAs may collect interference measurements, as follows. Thesemeasurements may follow a schedule that determines when and in whatdirection each MSTA transmits a test packet or a reference sequence,while other MSTAs simultaneously perform directional measurements. Atthe end of the interference measurement phase, each MSTA may know theinterference power when it points its receiving antenna towards each ofits one-hop neighbors.

A source MSTA may send PREQ message with an ID of an intendeddestination MSTA individually to each of its neighbors using appropriateantenna patterns. Airtime link metric value may be included in themessage (c_(a)=0 initially). A hop count may also be included(initialized to 0). The MSTAs that receive the PREQ message may updateit with the link metric for the previous link from the PREQ sender tothe current MSTA. However, the airtime link metric may be modified asfollows:

$\begin{matrix}{c_{a}^{\prime} = {\left\lbrack {O + \frac{B_{t}}{r^{\prime}}} \right\rbrack\frac{1}{1 - e_{f}}}} & {{Equation}\mspace{14mu} 6}\end{matrix}$where, r′ is the data rate for test packet transmission, includinginterference effect.

For a particular receive antenna configuration, the effectiveinterference power may be calculated based on the interferencemeasurements obtained previously. In case of multiple interferers, themax power, sum of all powers, or some weighted average may be used.

The airtime link metric may be updated with the value for the particularlink as follows:c _(a)(j)=c _(a)(j−1)+c _(a)′  Equation 7where, c_(a)(j): updated airtime link metric, c_(a)(j−1) is the value inthe received PREQ message and c_(a)′ is the calculated link metric forthe link from the PREQ source to the current STA.

If the MSTA has already forwarded a PREQ message for thesource-destination pair with a smaller airtime link metric within ashorter preceding predetermined duration, the MSTA may drop and notforward the current PREQ message. This may prevent unnecessaryforwarding of packets with inferior cumulative path metric. If the MSTAalready knows a path to the destination, then it may respond to the PREQsender with a path response (PREP) message with the cumulative pathmetric to destination. The PREQ message may not be forwarded towards thedestination in this case.

The destination MSTA may receive multiple PREQ messages from itsneighbors. It may then determine the optimum path based on the smallestcumulative airtime link metric. The destination MSTA may send a PREPmessage to the MSTA that sent the PREQ message with smallest metric. Itmay include the final cumulative metric calculated by it in the PREPmessage. The PREP message may be relayed back by each MSTA to itsprevious MSTA with the smallest cumulative metric at that point. Thismessage may get back to the source and therefore establish the optimumpath.

A regionally-aware link metric update procedure is described herein. Thefollowing describes example procedures to choose optimum network-widesource-destination paths by including inter-link effects in path metriccalculations. Accordingly, link metric calculations between a particularpair of MSTAs may take into account the interference caused byneighboring directional links and also the interference caused toneighboring links.

The link update procedure may include interference measurement andresult exchange. MSTAs may make directional measurements when a singleMSTA transmits at a time. In this case, each MSTA may transmit atraining field or a test packet towards the direction of each of itsneighbors, while other MSTAs may make signal strength measurements inthe direction of each of their neighbors. At the end of the interferencemeasurement phase, each MSTA may know the interference power when itpoints its receiving antenna towards each of its one-hop neighbors.

Each receiving MSTA may also send an interference measurement report tothe transmitting STA. The level of observed interference may be reportedin terms of the decrease in link quality due to interference caused bythe transmitting MSTA towards each of its neighbors. The reporting MSTAmay compute the airtime link metric impact, Δc_(a), to the transmittingMSTA and send in the interference report. This may be computed asfollows (assuming e_(ƒ) is the same in both cases):

$\begin{matrix}\begin{matrix}{{\Delta\; c_{a}} = {\left( c_{a} \right)_{interference} - \left( c_{a} \right)_{{no}\mspace{14mu}{interference}}}} \\{= {c_{a}^{\prime} - c_{a}}} \\{= {{\left\lbrack {O + \frac{B_{t}}{r^{\prime}}} \right\rbrack\frac{1}{1 - e_{f}}} - {\left\lbrack {O + \frac{B_{t}}{r}} \right\rbrack\frac{1}{1 - e_{f}}}}} \\{= {\left\lbrack {\frac{1}{r^{\prime}} - \frac{1}{r}} \right\rbrack\frac{B_{t}}{1 - e_{f}}}}\end{matrix} & {{Equation}\mspace{14mu} 8}\end{matrix}$

The link update procedure may include cumulative path metriccalculation. A source MSTA may send a PREQ message with an ID of anintended destination individually to each of its neighbors usingappropriate antenna patterns. An airtime link metric value may beincluded in the message. However, the initial value of the airtime linkmetric may not zero in this case. The sum of airtime link metric impact(Δc_(a)) values collected from the interfered may be the initial value.The airtime link metric c_(a) may be calculated as follow:c _(a)(0)=Σ_(i∈I) _(k) {Δc _(a)}_(i)  Equation 9where I_(k) is the set of all MSTAs in the interference zone of thesource MSTA when transmitting to k^(th) neighbor. A hop count may alsobe included (initialized to 0).

The MSTAs that receive the PREQ message may update it with the airtimelink metric c_(a) for the previous link from the PREQ sender to thecurrent STA. However, the airtime link metric may be modified asfollows:

$\begin{matrix}{c_{a}^{\prime} = {\left\lbrack {O + \frac{B_{t}}{r^{\prime}}} \right\rbrack\frac{1}{1 - e_{f}}}} & {{Equation}\mspace{14mu} 10}\end{matrix}$where, r′ is the data rate for test packet transmission, includinginterference effect. For a particular receive antenna configuration, theeffective interference power may be calculated based on the interferencemeasurements obtained previously. In case of multiple interferers, themax power, sum of all powers, and/or some weighted average may be used.

The airtime link metric may be updated with the value for the particularlink as follows:c _(a)(j)=c _(a)(j−1)+c _(a)′  Equation 11where, c_(a)(j) is the updated airtime link metric, c_(a)(j−1) is thevalue in the received PREQ message, and c_(a)′ is the calculated linkmetric for the link from the PREQ source to the current STA.

Before forwarding the airtime link metric to its neighbors, the MSTA mayupdate it for each individual neighbor as follows:{c _(a)(j)}_(k) =c _(a)(j)+Σ_(i∈I) _(k) {Δc _(a)}_(i)  Equation 12where I_(k) represents the set of all MSTAs in the interference zonewhen current MSTA transmits to its k^(th) neighbor.

If the MSTA has already forwarded a PREQ message for thesource-destination pair with a smaller airtime link metric within ashort preceding duration, it may drop the current PREQ message and maynot forward it. This may prevent unnecessary forwarding of packets withinferior cumulative path metric. If the MSTA already knows a path to thedestination, then the MSTA may respond to the PREQ sender with a PREPmessage with the cumulative path metric to destination. The PREQ messagemay not be forwarded towards the destination in this case.

The destination may receive multiple PREQ messages from its neighbors.It then may determine the optimum path based on the smallest cumulativeairtime link metric. The destination MSTA may send a PREP message to theMSTA that sent the PREQ message with smallest metric. The destinationMSTA may include the final cumulative metric calculated by it in thePREP message.

The PREP message may be relayed back by each MSTA to its previous MSTAwith the smallest cumulative metric at that point. This message may getback to the source and therefore establish the optimum path. This abovedescribed procedure may determine the optimum path in terms oftransmission rate, and the MSTA may determine a path that causes theleast additional interference to neighboring links along the path.

The link update procedure may include route setup intimation. After pathestablishment, each mesh MSTA in the chosen path may send a route setupintimation message to every MSTA within an interference zone associatedwith MSTAs transmitting in the direction of the next MSTA in the path.This may cause the neighboring MSTAs to adjust their transmission ratesto account for the interference from the newly setup link.

The neighboring MSTAs, upon receiving the route setup intimation, maysend a link metric update to each destination MSTA that has a pathpassing through that STA. This may cause the destination MSTAs tore-evaluate the path metrics for the path passing through the affectedMSTA.

Dual-band management frame prioritization is described herein. In adual-band mesh network, D-band management frames may be transmittedusing O-band messages. However, since such messages are normallytransmitted using contention based mode, in a highly loaded networkthese transmissions may be delayed. The following approaches may be usedto prevent such delays: prioritization of dual-band management frames;and/or contention-free transmission of dual-band management frames.

Dual-band management frame transmission in contention-free mode isdescribed herein. An MSTA may transmit dual-band management or actionframes during MCCAOPs to ensure contention-free transmission and alsofor schedule predictability. The owner MSTA may follow 802.11sprocedures for MCCAOP reservation, including sending an MCCAOP setuprequest element, and receiving an MCCAOP setup response element inresponse to the responder MSTA. These setup messages may be exchanged incontention-based mode.

D-band action frames, such as MCCA Advertisement frame, MCCAAdvertisement Request frame, MCCA Setup Request frame, MCCA SetupResponse frame, Mesh Link Metric Report frame and HWMP Mesh PathSelection frame, may be transmitted in these O-band MCCAOPs reserved fordual-band management frames. The duration and periodicity of theseMCCAOPs may be determined by the owner MSTA based on the timingrequirements of D-band action frames.

Prioritization of dual-band management frames is described herein. The802.11ae standard may include QoS management frames (QMF) support. Whenthe QMF service is enabled, some management frames may be transmittedusing an access category other than the access category assigned tovoice traffic (access category AC_VO) in order to improve the QoS ofother traffic streams. This may be achievable by the use of a QMFpolicy. A QMF policy may define the access categories of differentmanagement frames. The QMF MSTA may assign an access category to eachmanagement frame according to the access category assignments indicatedin the QMF policy that have been configured using the configurationprocedures.

802.11ae may specify a default QMF policy. It may define the accesscategory of each management frame based on management subtype value,category value and/or action value. However, mesh action frames may beassigned QMF access category AC_BE, corresponding to best efforttraffic. An additional management frame category for dual-band meshaction may provide D-band management frames transmitted on O-band withhigher transmission priority. Table 20 shows an example of a QMF policytable that includes, but is not limited to, a mesh action and/or adual-band mesh action category, and the following elements: managementframe subtype value; category value; action class; and/or QMF accesscategory.

TABLE 20 default QMF policy Management Frame Subtype Category QMF accessDescription value value Action class category Mesh Action 1101 13 0, 2,4-10 AC-BE Dual-band 1101 13 0-10 AC-VO Mesh Action

Although techniques described above consider 802.11 protocols, one ofordinary skill in the art will appreciate that the techniques areapplicable to other wireless systems and protocols.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.Although the solutions described herein consider 802.11 specificprotocols, it is understood that the solutions described herein are notrestricted to this scenario and are applicable to other wireless systemsas well.

What is claimed:
 1. A dual-band mesh station (MSTA) capable of operating in an O-band and a D-band and seeking to join a mesh network, the MSTA comprising: a receiver configured to receive O-band beacons from at least one MSTA in the mesh network, wherein the O-band beacons include D-band mesh information and a D-band beacon time interval; a transmitter configured to transmit D-band beacons in the D-band beacon time interval specified by the O-band beacons; on a condition a beacon response message is received via O-band, the transmitter configured to transmit D-band association information via O-band management frames to join the mesh network on the D-band; the receiver configured to receive a D-band transmit-receive (TX-RX) schedule from at least one neighboring MSTA in the mesh network including transmission schedule information and transmission direction information for one-hop and two-hop neighboring MSTAs, wherein a one-hop neighboring MSTA communicates directly with the dual-band MSTA and a two-hop neighboring MSTA communicates with the dual-band MSTA via a one-hop neighboring MSTA; and a scheduler configured to schedule contention-free concurrent transmissions with the one-hop and two-hop neighboring MSTAs in the mesh network in the D-band, based on the transmission schedule information and the transmission direction information, by communicating via O-band management frames.
 2. The dual-band MSTA of claim 1, wherein the D-band mesh information includes at least one of the following: a mesh identifier (ID), mesh configuration elements, a path selection protocol ID, a path selection metric ID, a congestion control mode ID, a D-band capability element, a beacon transmission timing, an D-band operating channel, and a beacon transmission interval.
 3. The dual-band MSTA of claim 2, wherein the D-band capability element includes at least one of the following: an antenna capability and a maximum transmit-receive (TX-RX) range.
 4. The dual-band MSTA of claim 1, wherein the D-band association information includes at least one of the following: sector-sweep feedback, and D-band mesh identification (ID).
 5. The dual-band MSTA of claim 1, wherein the transmitter is further configured to transmit D-band transmission information including at least one of the following: D-band TX-RX schedules, TX-RX beam orientations, a pre-determined interference table of one-hop neighbors, and a pre-determined interference table of two-hop neighbors.
 6. The dual-band MSTA of claim 1, wherein on a condition that no O-band beacons are received within a predetermined period: the receiver is further configured to scan in D-band.
 7. The dual-band MSTA of claim 1, wherein 802.11s is used in the O-band and 802.11ad is used in the D-band.
 8. The dual band MSTA of claim 1, wherein the O-band is less than 6 GigaHertz (GHz) and the D-band is greater than 28 GHz.
 9. A method for joining a mesh network, performed by a dual-band mesh station (MSTA) capable of operating in an O-band and a D-band, the method comprising: receiving O-band beacons from at least one MSTA in the mesh network, wherein the O-band beacons include D-band mesh information and a D-band beacon time interval; transmitting D-band beacons in the D-band beacon time interval specified by the O-band beacons; on a condition a beacon response message is received via O-band, transmitting D-band association information via O-band management frames to join the mesh network on the D-band; receiving a D-band transmit-receive (TX-RX) schedule from at least one neighboring MSTA in the mesh network including transmission schedule information and transmission direction information for one-hop and two-hop neighboring MSTAs, wherein a one-hop neighboring MSTA communicates directly with the MSTA and a two-hop neighboring MSTA communicates with the MSTA via a one-hop neighboring MSTA; and scheduling contention-free concurrent transmissions with the one-hop and two-hop neighboring MSTAs in the mesh network in the D-band, based on the transmission schedule information and the transmission direction information, by communicating via O-band management frames.
 10. The method of claim 9, wherein the D-band mesh information includes at least one of the following: a mesh identifier (ID), mesh configuration elements, a path selection protocol ID, a path selection metric ID, a congestion control mode ID, a D-band capability element, a beacon transmission timing, an D-band operating channel, and a beacon transmission interval.
 11. The method of claim 10, wherein the D-band capability element includes at least one of the following: an antenna capability and a maximum transmit-receive (TX-RX) range.
 12. The method of claim 9, wherein the D-band association information includes at least one of the following: sector-sweep feedback, and D-band mesh identification (ID).
 13. The method of claim 9, further comprising: transmitting D-band transmission information including at least one of the following: D-band TX-RX schedules, TX-RX beam orientations, a pre-determined interference table of one-hop neighbors, and a pre-determined interference table of two-hop neighbors.
 14. The method of claim 9, wherein on a condition that no O-band beacons are received within a predetermined period, further comprising: scanning in D-band.
 15. The method of claim 9, wherein 802.11s is used in the O-band and 802.11ad is used in the D-band.
 16. The method of claim 9, wherein the O-band is less than 6 GigaHertz (GHz) and the D-band is greater than 28 GHz. 